Tanning agents and process for making them



mama Dec. 19,1944

UNITED ST TES PATENT orrlcs assess son Erik Schirm, Des'sau, Germanyimted in the Custodian Allen Property No Drawing. Application June is, 1941, Serial No. 398,772. In Germany July 8; 1940 I BClalms. (01.261-124) This invention relates to new tanning agents and their production.

I have found that commercially valuable condensation products may be obtained if sulflte Waste liquor is condensed with aromatic sulfamides and with aldehydes, especially formaldehyde or substances giving of! formaldehyde under thereaction conditions. Bythis'process the tanning properties of the sulflte waste liquor are improved to such an extent that the condensation products will -form valuable tannins, while the sulfite waste liquor itself, as is known, can only be regarded as auxiliary tanning agents.

The term "sulflte waste liquor should be understood to mean the waste liquor obtained when disintegrating wood according to the sulfite aldehyde during the reaction, such as para-formaldehyde, trioxy-methylene, formaldehyde-bismprocess and the like,' or the concentrates or dry substances that are obtained by. evaporation and preferably such products freed from iron and lime.

Aromatic sulfamides or their nuclear substitution products suitable for use as raw materials for the present process are for instance: benzene sulfamide, 4-toluol suliamide, i-chlorbenzene sulfamide, benzene-1,3-disulfamide, diphenyl-4,4'-disulfamide, naphthalene-1,3,5-trisulfamide, carbazol-tetrasuliamide, benzoic acid- 3-sultamide, Z-hydroxy-benzoic acid-S-sultamide, benzoic acid-3,5-disulfamide, phenol-2,4,6-trisuliamide, 1-hydroxy-naphthalene-8-suliamide,

' 1 hydroxynaphthalene-S-sulfamid 3 sulfoacid and so forth, Other suitable sulfamides, for

, the present process, are those obtained by the reaction of onia with the resinous sulfoe chlorides obtained by sulfonation of aromatic the present process include formaldehyde, acetaldehyde, glyoxyl, acrolein, crotch-aldehyde, furfurol etc. or corresponding compounds giving 03 fite, methylal, hexa-methylene-tetramlne etc.

The process may be conducted also in such a manner that the preliminary condensation products are formed from the suli'amides and the aldehydes first and then these products are reacted with'the sulfite waste liquor. As known condensation products oi this kind there may be mentioned the N-methylol compounds of the suliamides and their halogen hydracid esters, that is, the N-halogen-methyi compounds of the sul-, iamides. Such compoundsmay be obtained-in a known manner, by the reaction of the aldehydes with. the sultamides, and with the proper amounts of hydrochloric-acid.

he conversion between theinitial materials and the sulflte waste liquor takes place in an aqueous medium by heating to temperatures oi compounds in the presence of carbon tetra:

as methyl-, fethyl-, hydroxyb, halogen-and like H groups or hetero-atoms and heteroatomic groups,

such as for instance ether.-, sultone-, ester-, sulionamide-, carbonde-groups and so forth.

The preferred aldehydes used as reagents in about 100.

l'he conversion is completed as soon as the condensation product will form a clear solution in water. i

Example 1 Six hundred forty parts by weight of sulflte waste liquor freed from iron and lime and evaporated to a powder, with a dry content of 93.6%, are stirred together with360 parts by:

volume of water until a homogeneous syrup is formed. Now 250 parts by weightof N-methylolp-toluol sulfamide are added and the mixture, after being rendered homogeneous by stirring, is heated to 90 and stirred at this temperature until a sample of the reaction mass forms a clear solution in a large quantity of cold Water. After dilution with water and adjusting to a suitable pH value the reaction product is ready for use as a tannin.

Example 2 .iiour hundred twenty-six by weight of a finely powdered ooercial ture of benzene- 1,3 disuitamide and benzene 1,4 disuliannde, such as is obtained by energetic sulronation of benzene with an excess of chlorsulfonic acid and conversion of the isolated it .7 lfi-disuliochloride and me.-1,d-disulfochloride with i w to ia, are ad to the syrupy sulfite waste liquor obtained acoo to Example 1 and the mixture thoroughly a. Thereupen 11d by weisht or a solution of 40% aqueous formaldehyde are stirred into this mass at a,

of bensenei t dryness at reduced pressure and at the temperature of a water bath. The residue which is obtained yields 888 parts by weight and may easily be ground whereupon it forms a brownish gray powder which is readily soluble in water. The product is an excellent tanning agent.

In the ai'oregiven example the benzene disulfamide may be replaced by 250-300 parts by weight or naphthalene-1,8,5-trisuliamide or naphthalene-1,3,6-trisuliamide or by the samejamount of a commercial mixture of isomeric naphtha1ene-' trisuliamides. With'the same-mode of workimz" a product is obtained which is similar to the afore described product.

Example 3 I ."rne benzene disuliamide'obtained to.

Example 2 is replaced by 266 parts by-wcight or a sulfamide having a nitrogen content of 10.5%,

V -whloh suli'amide had been'made by action of con centrated ammonia water upon a resinous sulfochloride obtained from naphthalene. The

mode or working is in other respects the same as according to Example 2; In this case also there 2,see,so9 i I is obtained a powdery tannin which is readily soluble in water.

Iclaim: i. A process for producing a tanning agent which comprises condensing a sulfite waste liquor with an aldehyde and an aromatic poly-sulfamide.

2. A process for producing a tanning silent which comprises condensing a sulnte waste liquor withjormaldehyde and a benzene disuli'amide.

'3. A process for producing a tanning agent which comprises condensing a suliite waste liquor with tormaldehyde and a mixture of benzene-1,3- disuliamide and benzene-1,4-disuliamide.

4. A new tanning agent, the condensation product of a sulflte waste liquor with an aromatic polysuliamide and an aldehyde.

5. A new taming agent, the condensation product o! a sulflte waste liquorjwlth formaldehyde p -v benzene disuiiamide.

go 6. A new tanning agent. the condensation prodnot of a sulflte waste liquor with formaldehyde and a mixture or benzene-1,3-disuliamide and benzerie-lA-disuliamide.

4 7. A process for producing a tanning agent 25 which comprises condensing a sulphite waste liquor with formaldehyde and a naphthalene trisulphamide.

8. Anew tanning agent, a condensation product of a sulphite waste liquor with formaldehyde 3 and a naphthalene trisulphamide."

:ERIK BCHIRM. 

